The game of billiards and related table top games have been known for many years. Such games involve movement of balls on a table top. Typically a ball is struck with an instrument such as a cue to move the ball around the table top surface for positioning, to strike and move other balls, and the like. In some variants, balls are struck into holes in or at edges of the table top called pockets. In other variants, balls are struck so as to contact in a particular way other balls on the table top and/or cushions that line the table top to keep the balls on the table top surface. These games have a variety of names including cue sports, billiards, pool, snooker, pocket billiards, among others. For clarity and convenience, such games will be referred to collectively as billiards or billiard.
Generally speaking, the most popular form of billiards involves a number of colored balls placed on a table. Over many years the sport has attracted significant public interest as a spectator event and also as a personal pastime or hobby, similar to golf and tennis. Because of its colorful nature there has been increased interest in applying modern video capture technology and computing and imaging technology to record or analyze game play. There are available sophisticated methods of video recording of game play, such as in tournaments or exhibits using booms or strategically placed cameras, where a director manually dictates which camera feed to use during play, and where a remote voice commentary is fed into the video record. There are also many examples of “do-it yourself” video recording from manually placed cameras, where the field of view covers the entire table and player activities from a distance and at a perspective view. There have additionally been attempts to place cameras directly over the table, using image analysis to locate the balls and perform ball tracking, but ignoring the view areas around the table and player's activities that are the prominent features of the simple recording of game play with video cameras.
Such attempts at video recording and image ball recognition systems, however, fail to be applicable to a wider general audience of billiard game players. A significant failure of prior attempts is the lack of an integrated approach to incorporate the lighting of the table, both forms of video recording and an audio record of ball sounds and player voices into one approach, at a low cost, and with the ease of use related to one single integrated apparatus.
For instance, to capture sufficiently high quality images of the balls to allow advanced game play by computerized image analysis, the billiard table surface should be substantially uniformly lighted. To achieve rapid, ball recognition by image analysis the scene segmentation portion of the image analysis procedure is most efficiently accomplished by having a flat uniformly lit background. Billiard tables, however, are typically lit using one or more light sources disposed above a center portion of the table such that lighting at the edges of the table is markedly worse than at the center. Although the World Pool-Billiard Association provides the following equipment specifications for lighting, such specifications do not suggest the level of uniform illumination typically needed for imaging projects: “15. Lights The bed and rails of the table must receive at least 520 lux (48 footcandles) of light at every point. A screen or reflector configuration is advised so that the center of the table does not receive noticeably more lighting than the rails and the corners of the table. If the light fixture above the table may be moved aside (referee), the minimum height of the fixture should be no lower than 40 inches (1.016 m) above the bed of the table. If the light fixture above the table is non-movable, the fixture should be no lower than 65 inches (1.65 m) above the bed of the table. The intensity of any directed light on the players at the table should not be blinding. Blinding light starts at 5000 lux (465 footcandles) direct view. The rest of the venue (bleachers, etc.) should receive at least 50 lux (5 footcandles) of light.” Under such specifications, uniform illumination sufficient for imaging analysis is not readily available. As a result, automatic image analysis of balls at table edges can result in inaccurate ball identification or insufficiently accurate ball location determinations. As a result, rapid automatic image analysis of ball movement and location cannot be accomplished efficiently and cost effectively with conventional billiard table lighting.
Additionally, there is a need to have one video recording of game play that can simultaneously allow for accurate ball movement and position, such as may be accomplished by image analysis in the plane of the table surface but at the same time, in the same video record provide the video views of player activity around the near periphery of the table.